NEW YORK, United States — In March, Victoria's Secret aired its annual swim special, an hour-long bikini bonanza starring a dozen of its supermodels. Filmed at the sun-drenched paradise of St. Barth's, such "angels" as Lily Aldridge, Candice Swanepoel, and Behati Prinsloo showed off the label's latest looks, Nick Jonas and Demi Lovato performed hit songs, and everyone played slow-motion beach volleyball to Salt-N-Pepa's Push It.

It was classic sex-infused advertising from a sex-infused brand. And it failed.

Two months later, parent company L Brands said it would shutter the swimwear business. While the company was exploring new territories to conquer, its home turf of bras and underwear had come under assault by a number of new rivals. Shares are down almost 30 percent since last October, and sales growth had slowed. Pressured by the rise of athleisure—workout gear you can wear in the gym and on the street—Victoria's Secret had to change its priorities.

The company came up with a two-pronged approach. It is pushing product lines that, in typical Victoria's Secret fashion, are being billed as seductive. The first is bralettes, an airy, more comfy style that lacks underwire and is being touted as no less enticing than the traditional underwired counterpart. After all this time spent telling women that cleavage-generating bras will make them more alluring, Victoria's Secret says women do not really need pads, after all. The question is: Can Victoria's Secret persuade shoppers that this is the new sexy?

The more seismic, second prong is the company’s decision to intensify its previously clumsy pursuit of the sports bra consumer.

“It’s absolutely imperative that they don’t put their head in the sand,” said Simeon Siegel, an analyst at Nomura Securities. Victoria’s Secret must embrace how the consumer and the market are changing. “And that’s one of their biggest strengths,” he said.

In recent months, Victoria’s Secret has ramped up its push to sell both sportswear and bralettes. In e-mails for the bralettes, the company assured customers that “no padding is sexy.” In a promotional video for Victoria Sport, various models–the same ones that show off the label’s lingerie–explain how hard they work out for their jobs as they jump rope, pump iron, and take shots at a punching bag while baring rippling abs and glistening with sweat.

“It’s unacceptable for me to show up and not be in shape,” one of them says in a voiceover. At one point, three models, clad in their skimpy workout gear, stretch next to each other in slow motion.

Victoria's Secret built a $7.6 billion business by owning the gold standard of what was considered sexually desirable women’s underwear. Ever since it started selling lingerie in 1977, the brand seduced shoppers by playing to their fantasies. Catalogs were mailed to millions of homes, their pages laden with busty women. An annual televised fashion show flaunted the rail-thin, toned bodies of the label’s most famous models.

Padded bras became Victoria's Secret sultry moneymaker. The promise was simple: Wear this bra, become a bombshell. As the definition of sexy changed, so, too, did Victoria’s Secret. Its models slimmed down and showed more skin. Then they became more athletic. Now, consumers demand intimate attire for different body sizes, a development that followed years of blowback over the unhealthy examples set by skeletal runway denizens. But no matter what Victoria's Secret sells, or its reasons for doing so, it all comes down to sexiness. That is why it has trademarked dozens of brand names that include the word “sexy,” slapping the tag on products from panties to perfume.

“That sexy image, that is who they are,” said Bridget Weishaar, an analyst at Morningstar. “But it’s a lifestyle brand. It’s not tied to a specific product line.”

Victoria's Secret has found itself losing ground to new online business models. Adore Me, a subscription commerce site, churns out new lingerie designs and keeps customers coming back with its VIP Membership program. True & Co. uses a quiz to help shoppers pick their bra type, then sends products to their door to try out, effectively bypassing the fitting room. Negative Underwear fancies itself the anti-Victoria's Secret, shunning the voyeurism of lingerie marketing for a simpler, comfort-first message.

To adapt, Victoria's Secret must change, Nomura's Siegel said. But as Weishaar noted, to capitalise on its brand, every product has to be seen as sexual. Sports bras, in particular, present a peculiar puzzle for Victoria's Secret. By nature, they are not overtly sexual they are performance products made for a specific task. Women want them to create a static, dry, and cool feeling. It is a tough sell to make moisture-wicking fabric, worn while you're sweaty and exhausted, come across as seductive.

Not too long ago, Victoria’s Secret made its first attempt at selling sports bras, trying to muscle in on such big brands as Nike and Lululemon. Early efforts were disappointing. Excess inventory languished in stores and warehouses when, in 2014, the company overestimated the popularity of the new items. Today, Victoria’s Secret executives remain committed to their sports business; now, they say, they are getting “good sales growth” out of it.

“We're in a business that has different fashion trends from time to time,” Stuart Burgdoerfer, L Brands chief financial officer, said on a call with analysts in June. “Hopefully, in most cases, we’re leading those trends, or certainly taking good advantage of those trends, in things like sports bras or bralettes. We think we're participating well.”

By Kim Bhasin; editor: David Rovella.